1. Field of the Invention
The present invention relates to a novel transporter protein which has a transporter activity for a hydantoin compound.
2. Brief Description of the Related Art
One of the known methods for producing amino acids using an enzyme is to asymmetrically decompose a 5-substituted hydantoin compound, which is inexpensive to chemically synthesize, to an optically active amino acid. This method for producing optically active amino acids from the 5-substituted hydantoin compound has a widespread importance in preparing medicines, chemical products, food additives, and the like.
The 5-substituted hydantoin compound is converted to an amino acid by a hydrolysis reaction using enzymes (A) and (B) as shown in the following Reaction Formula (I).
(A) An enzyme which catalyzes a hydrolytic reaction of the 5-substituted hydantoin compound to produce an N-carbamylamino acid (hydantoinase, hereinafter referred to as ‘HHase’).
(B) An enzyme which catalyzes a hydrolytic reaction of the produced N-carbamylamino acid to produce an optically active amino acid (N-carbamylamino acid hydrolase, hereinafter referred to as ‘CHase’. Generally, carbamylamino acid hydrolase may be also referred to as carbamylase).
To produce an optically active amino acid from a 5-substituted hydantoin compound, an optically specific enzyme may be used, such as (A) hydantoinase and (B) N-carbamylamino acid hydrolase, as follows.

Known methods for producing an optically active amino acid from a 5-substituted hydantoin compound typically use a microbial enzyme. Other known methods use a combination of a microbial enzyme and a specific chemical reaction. A method for producing amino acids on a large industrial scale using a microorganism or a transformant producing the above-described enzymes (A) and (B) is commonly used. However, in these methods, most of the enzymes which catalyze the reaction are in the cell. Thus, if a substrate has a poor membrane permeability, it cannot reach the enzyme in the cell, which may cause a problem in that the 5-substituted hydantoin compound cannot be effectively converted into the optically active amino acid. To resolve this problem, the cells need to be disrupted before the reaction to solubilize the enzyme. However, disrupting cells in industrial production is complicated. Furthermore, insoluble substances which are generated by the disrupting process possibly may prohibit product recovery after the reaction.